Low-Level Design for MAANG Interviews

A book-shaped table of contents for LLD interview prep: OOP fundamentals through SOLID, design principles, UML, design patterns, dependency management, reliability, concurrency, domain modeling, API design, testing, refactoring, classic interview problems, advanced architecture, and performance — cross-linking Object-Oriented Programming and Patterns instead of duplicating them.

1 — Introduction to Design Patterns

What a design pattern actually is, why the Gang-of-Four catalog still matters in interviews, and how to recognize which category a problem is asking for.

2 — Creational Patterns

The five creational patterns — Singleton, Factory Method, Abstract Factory, Builder, and Prototype — for controlling how and when objects get created.

3 — Structural Patterns

The seven structural patterns — Adapter, Bridge, Composite, Decorator, Facade, Flyweight, and Proxy — for composing classes and objects into larger structures.

4 — Behavioral Patterns

The eleven behavioral patterns — from Strategy and Observer through Visitor and Interpreter — for managing communication and responsibility between objects.